Locomotion through apertures when wider space for locomotion is necessary: adaptation to artificially altered bodily states

Abstract

The objective of this study is to describe the adaptability of the central nervous system to safely cross a narrow aperture when the space required for passage is transiently extended with external objects under different locomotor constraints. In one of four locomotion forms (normal walking, walking while holding a 63-cm horizontal bar with or without rotating the shoulders to cross a door opening, and wheelchair use), nine participants were asked to pass through an aperture created by two doors (the relative aperture widths were 1.02, 1.10, and 1.20 times their maximum horizontal dimension under each form of locomotion) without a collision. The kinematic analyses showed that, when the participants rotated their shoulders while walking and holding a bar, virtually the same locomotor patterns as those during normal walking were observed: shoulder rotation was regulated well in response to the width of an aperture, and no collisions occurred. When shoulder rotations were restricted while walking and holding a bar or using a wheelchair, a large reduction in the speed of movement was observed as the participants approached the door, and, furthermore, the modulation in speed was dependent on the width of the aperture. In addition, the participants crossed at the center of aperture more accurately; nevertheless, collision sometimes occurred (more frequently, during wheelchair use). These findings reveal that movement constraints on shoulder rotation are likely to be a critical factor in determining whether quick and successful adaptation takes place.

Perception of spatial requirements for wheelchair locomotion in experienced users with Tetraplegia

“…The tetraplegic participants showed accurate estimation about the space required for both familiar and unfamiliar wheelchairs. This was consistent with the previous finding demonstrating that able-bodied individuals showed accurate estimation about the space required for both normal walking and walking while holding an external object (Higuchi et al, 2006). These findings led us to conclude that adaptation to artificially altered body dimensions while maneuvering external objects may occur in a short time only when an individual is practicing a well-learned, familiar activity.…”

“…Their underestimation was not completely eliminated after a moderately long, 8-day practice period in which they tried to go through a door opening of various widths in a wheelchair. This was in marked contrast with an individual's superior ability to adapt to artificial extensions of body dimensions while walking (Higuchi et al, 2006;Hirose and Nishio, 2001;Mark, 1987;Mark et al, 1990). When walking while holding a shopping bag in one hand or a large box in front of the body, for instance, a wider space than usual is required.…”

“…Generally, individuals are able to walk through narrow passages without collision under these conditions. Higuchi et al (2006) demonstrated that, when rotation of the shoulders was free at the time of door crossing, participants were very successful in crossing a doorway while holding a 63-cm horizontal bar; virtually the same locomotor patterns as those during normal walking were observed. The length of the bar was very close to the width of a standard wheelchair, as used in many countries.…”

Insights into the neural control of locomotion from walking through doorways in Parkinson's disease

“…Even in healthy participants, this constraint might affect behaviour in several ways. For example, it could slow the walking speed (Higuchi et al, 2006) similar to the speed-accuracy trade-off captured by Fitts' law (Fitts, 1954). If PD participants have exaggerated responses to action-relevant visual information, then the response to door width should be unnaturally amplified in the PD group, so that a change in door width should have very marked effects on PD participants.…”

“…This type of paradigm has been used to show that participants scale many aspects of movement to visual features such as obstacles (Patla & Goodale, 1996) and doorways (Higuchi et al, 2006). A recent study employed such a method to study responses to doorways in participants with PD (Almeida & Lebold, 2009).…”